Alloy



Patented Sept. 25, 11934 PATENT OFFICE- ALLOY Horace F. Silliman,Waterbury, Conn., assignor to The American Brass Company, Waterbury,Conn, a corporation of Connecticut No Drawing. Application October 29,1932, Serial No. 640,333

2 Claims. (01. Ii-ll My invention relates to an alloy or alloys ofcopper, beryllium and nickel, which can be hardened and strengthened bythe heat treatment usually referred to as precipitation hardening.

The alloys of copper with beryllium have been made and have been wellknown for a number of years. When these two elements are in solidsolution one with another in percentages ranging from about 1 per centto 4 per cent beryllium, 99 per cent to 96 per cent copper respectively,the resultant alloys have the characteristic of becoming hardened andstrengthened by heat treatment. This heat treatment consists of firstquenching the alloy or alloys from a suitable temperature within therange 600 C. to 850 C. and then reheating for a definite length of timeat a suitable 'te "pe rature within the approximate range 200'-.- 1to350 C. The time required for this reheating depends on the temperatureemployed, being much shorter at the higher points of the temperaturerange. Thus for example, at a temperature of 275 to 300 C., the timerequired would be in the neighborhood of 1 to 2 hours.

There are structural changes in the alloy or alloys at these lowtemperatures that bring about the hardening. This method of hardeningalloys is known as precipitation hardening, age hardening and the like.

The alloy or alloys may or may not be cold worked by rolling, drawing,etc., after either or both parts of the aforesaid heat treatment.

One difficulty encountered in the manufacturing of the copper-berylliumalloys containing from 1 per cent to 4 per cent beryllium has been thatthe high temperature required for the first part of the precipitationhardening treatment produces grains of a very large size. This grainsize persists after the precipitation hardening treatment with theresultthat the finished product is coarse grained and low in percentageelongation as determined by the tension test.

I have found that the addition to the copperberyllium alloy containingfrom about 1 per cent to about 4 per cent beryllium, remainder copper,of a certain amount of nickel, will greatly reduce the grain sizeproduced by the required high temperature anneals, or that is, by thefirst part of the precipitation hardening treatment. In addition, thenickel benefits the procedure of casting and refines the grain of thecasting. It also gives increased or improved workability. The ad-:dition of nickel raises the temperature of recrystallizationof thealloy; in other words, if a -old worked copper-beryllium alloy begins tosoften,

cent.

as a result of recrystallization, under the application of heat at atemperature of 300 C., more or less, the addition of nickel to thatalloy will raise the temperature at which softening occurs by anappreciable amount. The addition of nickel to the copper-berylliumalloys greatly increases the percentage elongation that results from theprecipitation hardening treatment. The degree of increase in percentageelongation may be as much as ten times. The addition of nickel alsoincreases Youngs modulus of elasticity. In all of these cases theaddition of thegnickel is distinctly beneficial.

My preferred alloy to which this invention relates containsapproximately copper 97.25 per cent, beryllium 2.25 per cent, and nickel0.50 per However, I have found that the nickel will be of benefit inamounts ranging from 0.01 per cent to 1.00 per cent; the berylliumcontent ranging from 1 per cent to 4 per cent; the remainder being asubstantially pure copper. The heat treatment of the abovecopper-beryllium-nickel alloys is substantially the same as that for thecopper-beryllium alloys mentioned, the preferred reheating temperaturebeing from about 250 to 300 0., and as indicated, the time required forthe precipitation hardening varies with the temperature.

This copper-beryllium-nickel alloy is adapted to be used primarily forall wrought forms, the addition of nickel materially improving theworkability of the copper-beryllium alloy, and the hardening can be doneeither before or after wherein the content of beryllium is approxi--mately from 1 percent to 4'percent, the content of nickel from 0.01percent to 1.0 percent, and the remainder copper, the beryllium beingalways in excess of the nickel whereby the grain size is materiallyreduced and the workability improved over a similar copper-berylliumalloy without the nickel.

2. An alloy comprising approximately 97.25 percent copper, 2.25 percentberyllium, and 0.50 percent nickel.

HORACE F. SILLIMAN.

